CN102792022A

CN102792022A - Concentrated solar power system

Info

Publication number: CN102792022A
Application number: CN2010800499556A
Authority: CN
Inventors: A·H·斯洛克姆; J·布昂吉诺; C·W·福斯博格; D·S·科德; A·T·帕克森
Original assignee: Massachusetts Institute of Technology
Current assignee: Massachusetts Institute of Technology
Priority date: 2009-09-18
Filing date: 2010-09-20
Publication date: 2012-11-21
Anticipated expiration: 2030-09-20
Also published as: WO2011035232A2; WO2011035232A3; US20170010023A1; US9273883B2; US20110067690A1; AU2010295374A1; KR20120083425A; US9488386B2; CN102792022B; US20110067398A1; IN2012DN02495A

Abstract

A concentrated solar power system. Systems and methods for concentrating and storing solar energy are provided. A solar energy receiver for use with the systems and methods may include a container for holding a solar absorption material, such as a phase change material, and a cooled cover disposed above the container for condensing and collecting vaporized phase change material collected along an underside of the cover.

Description

The solar electric power system that assembles

Cross

The application requires in the U.S. Provisional Application sequence No.61/243 of submission on September 18th, 2009, and 763 and 61/243,769, and the U.S. Provisional Application sequence No.61/356 that submits on June 21st, 2010,882 preference and interests.All three applications are by through quoting in full merging in this article to them.

Technical field

The present invention relates to the solar electric power system and method, be used for high temperature solar-energy collecting and be stored in the receiver that is full of fluid.This energy stored can be used for generating.

Background technique

Large solar concentrator and stocking system that current popular is used comprise the solar reflector place usually, and light is focused on the receiver architecture of tower installation.This receiver architecture can be direct absorption-type (as, be downward through the fused salt on vertical surface) or cast (as, with the water that flows through pipe).These thermmal storage medium absorb heat energy, and under the situation of water, are transformed into steam, perhaps can be used to produce steam, supply steam turbine plant system commonly used to be used for generating.Heated medium can be transferred to the storage tank of insulation, and when no longer shining with the convenient sun, the medium from the heat of storage tank can be used for for power cycle (power cycle) heat being provided.

The solar electric power tower has many deficiencys, from their Economy of negative effect.For example, because boiler tube is uninsulated and is exposed to surrounding environment in the receiver, high heat loss causes because of cross-ventilation with from the radiation on the surface of heat in such system.In addition, Storage Media must upwards be pumped into the absolute altitude of boiler, and this requires sizable draw power.The result is that the whole efficient of solar energy tower type system is low relatively by-Yue 20%.Have, the investment cost of building the solar electric power tower of this heaviness receiver of supporting is high again.

Some shortcomings of the receiver of tower installation are overcome in other system, and the tower supporting secondary reflection mirror of these systems is introduced ground receiver to solar energy again, perhaps preferably partly is embedded in the receiver on ground.Aspect passive, using of secondary reflection mirror also reduces the efficient of solar energy converting as heat energy.Reason is overheated and damage in order to make the secondary reflection mirror, and the efficient of this system further receives the constraint of the maximum solar energy density that the secondary reflection mirror can bear.

Additional constraint to solar electric power system stores high-energy-density ability is in chemically stable temperature range by Storage Media and causes.The fused salt synthetic that uses at present such as the nitrate mixture, decomposes during near 600 ° of C when temperature, therefore limits maximum temperature, thereby limits the efficient of power cycle in energy storage density and the receiver downstream of this system.

Therefore, the solar electric power system that needs is: help the high-efficiency solar conversion, high density energy stores and durable continuous again power supply, preferably low investment cost.

Summary of the invention

The present invention provides the solar electric power system and method for convergence, and these system and methods solve the many problems and the restriction of above-mentioned solar electric power system simultaneously.In various embodiment; These system and methods utilize and to contain (normally high temperature) solar absorptive material, such as the solar receiver of phase-change material; Get up with solar-energy collecting device systems incorporate, this solar absorptive material plays the thermmal storage medium.This solar-energy collecting device system can be formed by the array of heliostat, and this heliostat array reflection and converge sunlight get into receiver.In this receiver; Solar radiation is absorbed by at least a portion volume of this absorbent material entirely, and converts the heat energy that can be stored immediately thus into, and is applied to; For example; As the source of process heat, produce the steam that supplies steam circulation system generating commonly used, or make working fluid preheating in the desalination circulation.

In certain embodiments, receiver is imbedded ground by (at least in part), and it is adiabatic that ground provides, thereby make the receiver based on ground become the heat reservoir more more economic than the receiver of tower installation.Heliostat can be placed in (for example, on the hillside) on the absolute altitude on the receiver, is effective as faceted downward beam optical apparatus (faceted beam-down optic) and works.Expense and the complexity with downward beam system relationship eliminated in this configuration, and this downward beam system is all often to comprise the hyperbolical reflector on the big tower basis of secondary and many elementary convergence power scavenging devices (power collector) on the pedestal of tower.

This receiver can comprise open containers, is used to keep phase-change material " groove " or " pond ", and places the lid on this container, and the loss that brings owing to vaporizing with the restriction phase-change material is retained in captive solar energy in the receiver with helping.Be included in the thermmal storage medium in the box container rather than in the boiler tube, allow to use the container material and the structure that can bear higher temperature, and also relatively cheap usually in addition.This lid can comprise cooling system, and the phase-change material that is beneficial to vaporize (normally fused salt synthetic) condenses and preserves, and makes spillage of material minimum thus.The phase-change material that condenses can form the reflecting layer at the downside of lid.Structure by container and/or lid form can comprise single inlet opening, and solar radiation is conducted through this hole and gets into.The air curtain of optional this inlet opening of leap can further reduce or prevent energy and phase-change material from this receiver loss, and prevent that phase-change material is by the atmospheric pollution of dust-laden and dirt.Change kind of a mode, this receiver can comprise door, for example is used for, and opens and closes this inlet opening with the intensity of solar radiation.

In certain embodiments, these thermmal storage medium are fused salt synthetics, and it is surpassing the temperature of 700 ° of C, and are chemically stable on the temperature up at least 1000 ° of C preferably.Will be the transfer of heat that stores in the fused salt to working fluid, the part of this synthetic can be mixed with colder fused salt, is used for being reduced to enough low value to the temperature of mixture, so that can guide its heat exchanger through the generation water vapor used always.Through after the heat exchanger, this salt is recovered, and gets into the storage circulation of receiver and/or colder fused salt.Change kind of a mode, for reaching higher thermodynamic efficiency, recuperator can be used, in this recuperator, from the salt of the heat of this case, transfer of heat to the colder salt that from steam generator heat exchange circulation, returns.In certain embodiments, this salt mixture near or surpass on the temperature of 700 ° of C and get into heat exchanger, help reasonably the directly use of air Bretton (Brayton) power cycle efficiently, this Bretton power cycle does not require water-cooled.

In certain embodiments, in the receiver fused salt on demand from the top of container by pumping, to steam generator or other power cycle constant substantially power input (power input) is provided.Be pumped into the bottom of container from the cold salt of steam generator.This container can comprise the demarcation strip of insulation, this demarcation strip being provided between the heat of thermic layering and the cold layer in this container physics with barrier heat.This demarcation strip can be vertically, move down; Allow fused salt through the annular clearance space (clearance space) between this plate and the container wall; Crossing this plate moves; Make heat and volume cold salt remain in the temperature range that needs (for example, on stationary temperature substantially), so that continuous running.The result is, even when the sun no longer shines, the mean temperature of salt descends in the container, and the steam of high temperature also can be provided.In addition advantageously, because the total volume of salt does not change in the container, the top surface of salt is still on the focus of solar farm (solar field).

Solar electric power system according to various embodiment provides energy storage, compensates the obnubilation retaining being arranged or lacking sunlight night.Therefore, they help around the clock to satisfy base load power demand (power needs), need not the support of burning mass mineral fuel or expensive (and not available as yet) tentative battery storage device.The result is, the disclosed different solar electric power system of this paper not only provides energy-efficient, and exempts from the capacity installed significantly for utility power company provides.

On the one hand; The present invention provides the solar electric power system of convergence; Comprise solar receiver based on ground, and a plurality of heliostat, these heliostats are configured to make them directly to reflect the solar radiation of injecting (promptly; Not further reflection), get into the inside of receiver through the receiver hole.This receiver is fit to hold solar absorptive material (this solar absorptive material itself can be the parts of this system), and being used to make solar energy converting is heat.This solar absorptive material can comprise or be made up of phase-change material in fact; This phase-change material can be translucent; And can by liquid form comprise fused salt (such as, for example, chloride salt, fluoride salt, carbonite, nitrite or their mixture).In certain embodiments, this fused salt is a chloride salt, and this phase-change material also comprises hydroxide, when contacting with humid air with this fused salt of box lunch, reduces the generation of HCl.In addition, in certain embodiments, this solar absorptive material comprises nanoparticle mixture, to improve the solar radiative absorption characteristic of this absorbent material.

Heliostat can be positioned on certain absolute altitude of hole top of receiver (for example on the hillside), and is directed, so that through the solar radiation that pass or that be focused of this hole, mainly be directed on the surface of solar absorptive material.This receiver can be embedded in ground at least in part.In certain embodiments, this receiver comprises container and is placed in the lid on this container.So heliostat can be placed on the certain absolute altitude below the receiver and be directed, so that pass the downside that the solar radiation in this hole is drawn towards this lid.Should can be configured to help the heating solar absorbent material to arriving at least about the temperature in 1000 ° of C scopes based on the receiver on ground and heliostat together at about 600 ° of C.

On the other hand, the present invention is directed to a kind of solar-energy conversion systems, it comprises solar receiver, heat exchanger and mixing chamber, and this solar receiver is fit to hold and is used for solar energy converting is the solar absorptive material of heat energy; This heat exchanger is fit to arrive working fluid to the transfer of heat energy from the solar absorptive material that liquefies, and is used to produce mechanical energy and/or electric energy; And this mixing chamber is fit to mix the solar absorptive material of liquefaction with colder solar absorptive material from heat exchanger outlet; So that before solar absorptive material to the heat exchanger that transmits this liquefaction, reduce the temperature of the solar absorptive material of this liquefaction.

This system can also comprise the thermal energy storage storehouse that is communicated with the receiver fluid, and/or is in (and being communicated with heat exchanger and mixing chamber fluid) the one or more thermal energy storage storehouse in the middle of heat exchanger and the mixing chamber.This solar receiver can be fit to hold temperature and arrive at least about the phase-change material in 1000 ° of C scopes at about 600 ° of C.In certain embodiments, this system comprises and is used for the thermal power transfer of working fluid is the turbo machine of mechanical energy, and/or by this turbine driven generator, so that convert mechanical energy into electric energy.

The present invention also provides a kind of energy-producing method of solar electric power system of using convergence on the other hand.The step that this method comprises has: the guiding solar radiation gets into solar receiver through the receiver hole in individual reflection; So that solar-energy collecting in this receiver; Thereby heating be comprised in this receiver solar absorptive material at about 600 ° of C at least about the temperature in 1000 ° of C scopes; From the transfer of heat energy of heated solar absorptive material to working fluid, and produce one of mechanical energy and electric energy at least with this working fluid.

In certain embodiments, this heat energy is being transferred to working fluid above on the temperature of about 700 ° of C.This working fluid can be or comprise air, and this energy generation step can be utilized direct air Bretton power cycle (it does not require water-cooled in certain embodiments).In certain embodiments, this heat energy is transferred to the working fluid the heat exchanger from heated solar absorptive material.This method can comprise the solar absorptive material that makes from the liquefaction of receiver in addition; The step of mixing with colder solar absorptive material from heat exchanger outlet; So that before the heat exchanger, reduce the temperature of the solar absorptive material of this liquefaction at the solar absorptive material that transmits this liquefaction.

Another aspect more of the present invention relates to a kind of solar receiver.This receiver pack contains the container of the inside that is fit to hold solar absorptive material, and is placed in the lid on this container.This container definition is radiated on the solar absorptive material to allow solar radiation, and in certain embodiments, is formed into oral pore with this lid along the perforate on top, so that allow solar radiation to pass through this hole.This system also comprises cooling system, the condensing of the solar absorptive material of at least a portion vaporization that is beneficial to be collected along the downside of lid.The downside of this lid can be fit to reflect the solar radiation of irradiation to this internal tank, and can form the concentrator of non-imaging.In certain embodiments, this concentrator comprises and downside at the lid of the solar absorptive material that the condenses combination that covers collection.This lid can be fit to return to the solar absorptive material that at least a portion is condensed the inside of this container.

In certain embodiments, this receiver comprises at least one convection current trigger unit, is placed on or near the bottom of this internal tank.This convection current trigger unit can be, or comprise the element of taper substantially.This system can also comprise door; Randomly be incubated; Be used to close this inlet opening to reduce heat energy loss from this receiver; And stop mass transfer through this hole, perhaps comprise the air curtain of crossing over the inlet opening, to reduce heat energy loss and the mass transfer (mass transfer) that reduces through this hole.

In aspect another; Provide a kind of method of catching solar energy that is used to generate electricity; This method comprises: the inlet opening of guiding solar radiation through receiver (this hole is formed by container and/or the lid that is placed on this container, and this container has the inside that solar absorptive material is wherein arranged of exposure); Cool off the vapor condenses that this lid makes the solar absorptive material generation of liquefaction; And the inside of being returned at least a portion by condensing vapour this container.The solar absorptive material that is cured that is deposited on this lid downside can be melted, and for example, as the result of the solar radiation of direct irradiation on this is cured material, and/or leaves the result of the solar radiation of the upper surface of material in the receiver as reflection.In certain embodiments, this method also comprises: form the air curtain of crossing over the inlet opening, to reduce heat energy loss and/or mass transfer; And/or bring out phase-change material in this container convection current (as, use be placed on or near one or more convection current trigger units of the bottom of internal tank).

In aspect another; Each various embodiment is to a kind of solar receiver; It comprises and is fit to hold and the structure of container that seals fused salt substantially; And flatly be placed on the demarcation strip that can vertically move in this structure of container, so that be separated into the upper and lower to this structure of container.This structure of container definition allows solar radiation through getting into the inlet opening of this receiver, and this inlet opening can be closed by door, and this is the part of this receiver in certain embodiments.This demarcation strip forms the annular space space, allows fused salt between the upper and lower of this container, to flow.The radial dimension in this annular space space can be selected; So that prevent the mechanical bond between demarcation strip and the container substantially; And/or make the relative movement of demarcation strip in the container, promote the salt plume to discharge (plume expulsion) and the mixing of (like a side) on the opposite direction of demarcation strip motion in heat.

This receiver can also comprise the vertical motion actuating system, with the vertical position of control demarcation strip.Be used to drive this actuating system so that the controller that demarcation strip moves, also can be involved.This controller can move demarcation strip; Be added and by a side pumping salt with convenient solar energy from demarcation strip heat; Pass through heat exchanger; And get back to a cold side (being the bottom of container) and when extracting heat energy out, make the salt on the side (that is, generally being the top of container) of this demarcation strip heat keep steady temperature substantially.In other words; This controller can move demarcation strip; So that make the net heat increment of receiver; Substantially with the sensible heat that is moved to the fused salt on top from the bottom (sensible heat) increment balance, and make from the net heat of receiver and extract out, substantially with the fused salt that moves to the bottom from the upper part the loss balance.This controller can also move this demarcation strip so that make the position of this demarcation strip, substantially with this structure of container in border between fusing salt deposit heat and cold of thermic layering overlap.

This demarcation strip can be made up of with the alloy of creep or steel plate with ribbing anticorrosive, perhaps comprises the alloy of anticorrosive and creep or steel plate with ribbing.In addition, it can comprise insulation refractory ceramics layer.When this receiver was melted salt and is full of, demarcation strip can be floating with meeting ground basically.In certain embodiments, this demarcation strip comprises hollow tubular structure.The upper surface of this demarcation strip can be veined, be coated and/or oxidized, to strengthen solar absorptance and to reduce specular reflectivity.

Again on the one hand, be that this container is separated into the upper and lower by the demarcation strip of level to a kind of method that stores solar energy in the container that is capped at the maintenance fused salt, wherein this demarcation strip is reserved the annular space space, supplies salt therefrom to flow through.This method comprises: in this container, receive solar energy, thus fused salt in the top of heating container; Move demarcation strip vertically,, keep minimum at least temperature difference so that constantly respectively between the mean temperature of the fused salt of this top and this bottom; And the fused salt heat extraction from the top of container.

This method can also comprise, and according to through the solar energy intensity by the inlet opening of the container that is capped definition, opens and closes the door of this inlet opening.Heat extraction can comprise, and delivers to heat exchanger from the charming fused salt that the top pumping of this container is hot, and returns to colder salt the bottom of this container from this heat exchanger.The total volume of fused salt in this container upper and lower can be held constant basically.This method can also comprise the lid that cools off this container effectively, and from the heat that the lid that is cooled is effectively extracted out, can be used to the fluid in preheating power cycle and/or the desalination circulation.In certain embodiments, the salt of vaporization is condensed at the downside of the lid that is cooled effectively.

Description of drawings

Noted earlier will being more readily understood from detailed description below in conjunction with accompanying drawing, in the accompanying drawing:

Fig. 1 is the diagrammatic side view according to the solar electric power system of some embodiments of the invention, and this system comprises heliostat and the receiver at the bottom of this mountain that is installed in the hillside;

Fig. 2 is the perspective illustration according to some embodiments' heliostat array;

Fig. 3 is the small-scale solar electric power system diagrammatic side view according to some embodiments' the receiver that comprises inclination;

Fig. 4 is the perspective view according to some embodiments' the solar receiver that single inlet opening is arranged;

Fig. 5 A is the different perspective views according to some embodiments' the solar receiver that two inlet openings are arranged with 5B;

Fig. 6 A and 6B be according to some embodiments, the profile perspective that to be respectively the solar receiver that tilts join with it and heat exchanger;

Fig. 7 illustrates the velocity distribution schematic representation of air curtain according to some embodiments;

Fig. 8 illustrates a sets of computer simulation image of the effect of convection current trigger unit according to some embodiments;

Fig. 9 A and 9B be according to some embodiments, is respectively demarcation strip at upper/lower positions with at the profile perspective that is separated solar receiver of last position;

Figure 10 is a curve, according to some embodiments, two day-night cycle of the sun power that is input to the solar receiver that is separated is shown, and corresponding demarcation strip position;

Figure 11 is a flow chart, and the method according to some embodiments is shown, and is used for confirming the demarcation strip position being separated solar receiver;

Figure 12 is the side view of the solar receiver container that is full of salt that is separated, to different radial clearances between demarcation strip in the container and the wall, the contrast of fused salt plume is shown;

Figure 13 is a flow chart, and the method according to some embodiments is shown, and is used to be designed for the demarcation strip of the solar receiver that is separated; With

Figure 14 is a skeleton diagram, and thermal energy storage, transfer and power generation system according to some embodiments are shown.

Embodiment

1. solar-energy collecting device system layout

Convergence solar electric power system according to each various embodiment of the present invention generally combines solar reflector place and hot receiver, and this receiver for example comprises the container that is capped.Figure 1A illustrates the exemplary configuration 100 of this system, and heliostat 102 wherein can be followed the tracks of the solar reflector of solar motion, is installed on hillside or other slopes 104.The reflecting surface of heliostat can have parabolic shape.In the operation, heliostat 102 is oriented usually, so as to reboot the sunlight injected directly get into near the slope at the bottom of or receiver 106 at the bottom of the mountain, as shown in the figure; Do not need secondary reflector.Under the condition that very high solar energy injects, some heliostats 102 can misalignment or misorientation, in order to avoid receiver 106 is overheated; Yet, such as below discussion, receiver 106 is designed to allow and operates in far away surpassing on the temperature of common system.

Receiver 106 comprises and keeps thermmal storage fluid 109, such as the synthetic of fused salt or the container 108 of other phase-change materials.Container wall can be incubated.In certain embodiments, insulation is through imbedding receiver 106 major parts in the ground, only reserves that receiver lid 110 and inlet opening 112 realize, solar radiation can get into through ground this inlet opening 112, and is as shown in the figure.The solar radiation that is reflected and leaves heliostat 102 and pass through inlet opening 112 can or directly be incident on the surface of thermmal storage fluid, perhaps is incident on and covers 110 downside, depends on that its gets into the angle on receiver institute edge.Penetrate the solar radiation of store fluid, be absorbed by the path of volume along it.Captive solar energy can be distributed to whole pond through convection current, and this convection current can become more effective with the optional convection unit 114 on bottom that is positioned at container 108 and/or the wall.

In some preferred embodiments, this thermmal storage fluid is the high temp. salt synthetic.That is the synthetic of Undec one or more salt under the temperature of about 700 ° of C in about 1000 ° of C or the higher scope.Use the high-temperature storage medium, allow the heliostat array very a large amount of solar-energy collectings in receiver, and can cause the higher energy efficiency of this system.At the pool surface of fused salt, temperature reaches the degree that makes some fused salt vaporizations usually.The salt steam of vaporization rises, and is deposited on and cover 110 downside, and this lid 110 can be cooled effectively and condense and/or solidify with promotion.Be radiated at the sunlight that is reflected on the salt of curing, can it melted again.As the result of condensing with melt process, be formed on the salt deposit that covers and constantly filled up again.

The draw isometric view of system of Fig. 2, this system have dozens of heliostat 102 to be installed on the hillside 104 and guide solar radiation to get into and be positioned at the receiver 106 on the ground level 116.Yet exemplary systems can comprise thousands of heliostats, and these heliostats can be arranged by array or another kind of mode, depend on local landform.If as shown in the figure, this receiver 106 is placed on (or imbedding) smooth ground 120, from this mountain some distances are arranged, can obtain so also to be positioned at the higher efficient of configuration on this mountain than receiver.In some preferred embodiment, the distance of receiver 106 at the bottom of the mountain is about the half the of heliostat place radius.In the space at the bottom of the mountain and between the receiver, electro-optical package commonly used can be installed generate electricity to utilize this available space, thus the repayment of increase investment in land.

Fig. 3 small-scale embodiment 300 of the present invention that draws, this embodiment's the heliostat array that comprises two row 302,304 injects sunlight in the cylindrical receiver 310 of inclination.In the example that is illustrated, planar mirror heliostat 306 uses with 308 combinations of solar energy trap.This solar energy trap 308 is avoided needing a large amount of inlet openings, otherwise these inlet openings possibly cause significant heat loss.In a further embodiment, the parabolic reflector heliostat of well focussed performance is arranged, can be used in the minisystem.

In a kind of other configuration, the receiver container is installed in the top of solar column.Lid is placed on the container.Sunlight is reflected and leaves the heliostat that is positioned at the following absolute altitude of receiver, and is drawn towards the downside of this lid, and there, sunlight is redirected in fusing salt pond or the container on other solar absorptive materials.The lid of above being similar to Fig. 1 being described, this lid can be cooled on one's own initiative or passively, so that the salt of permission vaporization condenses and forms the mirror surface of filling up again voluntarily.Ring edge or dripping eaves may be provided in the downside of lid, get back in the pond to guide down the fused salt that drips.In addition, all even smooth salt deposit is a high reflection, and self can be used as reflector, eliminates necessity of below mirror surface, removing the salt deposit.Reflecting surface based on salt also has the advantage that surpasses the regular reflection mirror, even by very high strength irradiation, also can not be damaged or destroy.This system can comprise underground storage tank, and it receives heated salt through pipeline from the receiver container.Pumping can promote cold salt to the receiver case from this storage tank, and the salt of heat then flows through ponding to falling tube and get back to this storage tank.

2. solar receiver

According to the solar receiver of certain embodiments of the invention, can comprise the container that is used to keep thermmal storage fluid (like, fused salt) and place the lid on this container, shown in Fig. 1 signal.Typical container can have tens of meters diameter and several meters height; Such container can keep the thousands of tons of fused salt, and is fit to supply the receiver based on ground to use (for example, as shown in figs. 1 and 3).The shape of this container for example can be cylindrical, bow shape or cube.This container bottom and sidewall can be processed like iron, chromium, nickel, molybdenum and manganese by metal.The general type of liquid salt container has the crust of being made by stainless steel or inconel, and the interior lining of refractory brick.Will be from the fused salt heat extraction, the heat exchanger that contacts with vessel surface can be used.Change kind of a mode, salt can be pumped into the outside heat exchanger of receiver, and it can be used to produce steam there.From the wherein stocking system and the method for the fused salt of heat extraction, be used for other processes commercial and industry and use, those skilled in the art are known.

Be placed in the lid on the container, can make lining with refractory brick equally, and can be connected with this container along the top edge of at least one container wall.In some preferred embodiments, this covers the space on the closed container basically, only on a side, reserves single inlet opening.In certain embodiments, this hole area of two square metres of having an appointment.For the salt avoiding vaporizing with in company with its loss of energy through this hole; This receiver can comprise door or similarly install; With this hole of Temporarily Closed (particularly during dark or low solar energy intensity), perhaps generate the air curtain of crossing over this hole, as discussing in more detail below.

The draw front 3-D view of exemplary arc receiver 400 of Fig. 4, this receiver comprises container 402, lid 404, hole 406 and several heat exchanger windows 408 that is full of salt.Such arc receiver for example can be used in the face of covering the heliostat array at 90 ° of angles.On typical hillside, two such receivers and heliostat array can be used.

Because the temperature that fused salt raises, especially on the surface in pond, salt stands some vaporizations usually, and this steam will condense in its temperature on the surface below the melting point.In each various embodiment, this lid is cooled off (for example using cooling tube 120, as shown in Figure 1) overleaf by air or water, and the lid downside thereby present such condensation surface.(if the downside of container cover is metal and remains on the temperature that is higher than fusing point, and it is with rapid oxidation and fade, and causes the reflectivity of the sunlight of scattering in the receiver is reduced).Because the conductivity coefficient of the salt that condenses is more much lower than the liquid salt, so it can be used as protective coating.Transfer to the heat energy of the fluid of cooling from the salt of heat, can be used to the water of pre-heated flow, otherwise be recovered and send to power cycle to increase efficient to steam generator.

The salt condensed layer can run up to stable state thickness, also can experience repeatedly phase transformation, forms smooth solid-liquid-gas blanket at the downside that covers, and this layer is high the reflection, thereby constitutes durable reflector.It is compared with the surface of water body, can strengthen the Grazing incidence reflection, thereby reboot the sunlight that does not have the direct irradiation salt pond from heliostat.In addition, the salt deposit at the lid downside can reboot the radiation of leaving the pool surface scattering and return in this pond.For strengthening this effect, this lid can be bent, and is preferably formed as the concentrator of non-imaging.The shape bending of this lid or that tilt also allows fused salt to flow backward, gets into this container and is caught by this container again.

Fig. 5 A and 5B draw respectively another exemplary receiver embodiment's three-dimensional side view and three-dimensional portion section front view.At this, receiver 500 comprises big hydrostatic column 502, and this container 502 is set up the chamber 504 of salt (not shown).Sunlight can be assembled through two holes 506,507 from two heliostat arrays.Usually because 0.01 radian divergence of sunlight light expansion, and through can not be always with from the vertical hole of each light beam of each heliostat be focused intersecting of light beam, spend arcs so each heliostat array forms 90 °, to control the size of light beam.For prevent through a hole (as, 506) sunlight that injects receiver penetrate at once other hole (as, 507), this receiver comprises catoptric arrangement 508, this catoptric arrangement 508 for example can be to hang the cone-shaped structure that gets off from container cover.In certain embodiments, this catoptric arrangement 508 has structure heat exchanger within it, makes the surface of salt vapor condenses at it, thereby forms protection and reflectance coating, is similar to the salt coating of this above-mentioned lid downside.In certain embodiments, lid 510 (half of this lid that only draws among Fig. 5 B is to appear the inboard of receiver), or the part of lid are dismountable, are beneficial to load salt and/or maintenance.

The draw cross section view of the cylindrical receiver 600 that tilts of Fig. 6 A for example can supply solar electric power shown in Figure 2 system to use, and Fig. 6 B cross section view of heat exchanger interface of cylindrical receiver 600 of this inclination that draws.In this embodiment, sunlight can use the energy collection device 208 of convergence to assemble, and can be mapped to the surface in fusing salt pond 604 in this container through inlet opening 602.The part of sunlight is reflected in the salt and through the salt volume and is absorbed, and another part of this light is reflected and leaves this pool surface, leaves thereafter and covers 606 downside, and this lid can be cooled and be beneficial to condensing of salt, so that protection and reflectance coating are provided.In certain embodiments, this lid is a plane shape, and is as shown in the figure.Generally speaking, the shape of lid can be by the known mode of those skilled in the art, and is optimised according to the law of diffuse reflection optics.

This salt pond 604 can be surrounded by refractory liner 608, and this refractory liner is encased by canister 610 again.In certain embodiments, the window 612 in the refractory liner can make heat flow heat exchanger 614, and this heat exchanger has inlet/outlet 616, is used to heat secondary salt transfer of heat loop, uses in the heat treatment industry of being everlasting as usual, or is used for the open steam generation.For heat exchanger 614 is coupled by low stress mode and container 610, in case high temperature creep, liquid metal 618, such as, for example, antimony, tin, magnesium, aluminium or their eutectic can be used.In addition, be to reduce conduction and convection loss, this container 610 can insulation layer 620 (as, be similar to the thermal insulating material that is used for the covering high-temperature steam pipe in the steam turbine plant system) cover.The bottom 622 of container 610 preferably also is incubated, and structurally is fit to the weight of this system of supporting in addition.Satisfy the material and the structure of these requirements, by broad research, so that in other commercial and industrials are used, use, this is that those skilled in the art are known.

In each various embodiment, the vapor pressure of the salt of high temperature melt under the situation that has no the alleviation means, can cause the remarkable loss through the salt steam of this inlet opening.These proportion of goods damageds depend on the temperature and the composition of salt, and depend on the details in receiver and hole.To the wind speed of 5m/s on the NaCl/KCl salt mixture of 850 ° of C and the inlet opening, these proportion of goods damageds are approximately 0.2kg/m through calculating ²/ h.Such loss of salt not only makes fills costlyly again, and reduces the energy efficiency of system, follows corresponding transfer of heat loss because cross over the mass transfer of inlet opening.Be the salt steam effusion receiver of anti-devaporation, each various embodiment of the present invention can comprise the air curtain of crossing over this hole.This air curtain can be by building in this lid, or the one or more electric power blowers that are placed on carrying pipe at a distance produce.

Fig. 7 illustrates along the width of air jet and the velocity distribution of length, and this air jet has width e at blower export.Crossing over the mass flowrate of this air jet, is the function of its width, length, thickness and outlet velocity.The power requirements of blower depends on these parameters equally, and therefore, these parameters can be selected, so that make the efficient of air curtain, that is, and the ratio maximization of the power that the power of saving owing to this curtain and blower require.In certain embodiments, this outlet velocity can be adjustable.A kind of suitable air curtain type; Especially the more details that concern between the power-balance of air jet parameter, enviromental parameter and curtain; Can be at Adam Taylor Paxson " Design and Validation of an Air Window for a Molten Salt Solar Thermal Reciever " (in June, 2009) (Bachelor of Science thesis; Massachusetts Institute of Technology) finds in, merge this article in this paper through quoting in full.

In certain embodiments, this receiver comprises deburring sharply, or the convection current trigger unit of " tip is arranged " (as making coniform), is placed on the bottom or wall of container, and is as shown in Figure 1.These convection current trigger units can maybe can be born other stable materials of fusing salt pond discal patch spare and processed by molded or cracked silicon carbide piece.They work as hot nucleation place, and prevent its thermic layering, and the convection current that this hot nucleation place starts and/or strengthen fused salt in the container mixes.Therefore, they help to make focus in the salt minimum and prevent the overheated and boiling of upper surface in salt pond.Fig. 8 shows the Computer simulation results that convection current trigger unit temperature field in the container of bottom is arranged.

In certain embodiments, this receiver container is separated plate (usually by horizontal positioned) and is divided into the upper and lower.Fig. 9 A and 9B are by the three-dimensional cross section view exemplary receiver that is separated 900 that draws.In the operation, when needs start [thermodynamic, the fused salt of 902 pumping heating from top.For example, the fused salt of heat can be directed to the inlet of exchanger, and the colder salt that withdraws from heat exchanger can be returned the bottom 904 that gets into the receiver container by pumping.The result is, this fused salt thermic layering promptly, is formed with the salt deposit of (usually being non-linear) temperature gradient between container top and bottom.

The demarcation strip of physically opening the upper and lower of container in 902,904 minutes 906 can be adiabatic, thereby also between layer heat and cold of thermic layering, thermodynamic barrier is provided.In certain embodiments, this plate is by anticorrosive and alloy creep, or steel plate with ribbing formation, and by refractory brick or the insulation of refractory ceramics layer.Plate although it is so is heavy, but the thickness of thermal insulation fire-resistant brick appropriateness is enough to make it floating with meeting ground in fused salt.Change kind of a mode, hollow, tubular structure can be used to make partition plate structure near floating with meeting ground.The hollow tube of this structure or chamber, can be designed to has a little internal pressure on operating temperature, so that the stress in the wall of chamber is minimum.For example, this demarcation strip can be made up of a series of cappeds pipe or other suitable chambeies.

The light that gets into receiver can in depth penetrate fused salt, so that its at least one fraction is mapped to demarcation strip 906, causes convection current, thereby is heated to uniform high-temperature to salt hot in the top 904.This demarcation strip can be through actuation cord 908, connecting rod or other power transfer elements, through cylinder or through any other the suitable actuating system parts that can in the environment that surrounds receiver 900, operate, motion up or down vertically.Annular space space between demarcation strip 906 and the container wall (or " radial clearance ") when this plate 906 is moved, allows salt to cross upper and lower 902,906 motions of the demarcation strip between 904.For example, when this demarcation strip 906 was moved upward, fused salt flow to this bottom 904 from this top 902 through the annular space space.This receiver can comprise controller 910, and it drives vertical actuating system, so that make demarcation strip by (for example, the use of this receiver is as solar receiver or as the source of heat energy at this moment with transient operation state and condition; The intensity of incident solar radiation; Through this receiver by the speed of the salt of pumping, or the like) the relevant speed that is fit to and move along correct direction.This controller 910 can implement to be used for the method (for example, as following said with reference to Figure 11) that definite this suitable demarcation strip moves by hardware, software or their combination.For example, this controller 910 can be or comprise the special electronic circuit, or with the general computer of appropriate software programming.

Fig. 9 A and 9B illustrate conceptually, and demarcation strip 906 positions how to inject receiver with solar energy and heat energy is extracted out relevant from receiver.Shown in Fig. 9 A, at end on sun-drenched daytime, demarcation strip 906 has moved down, and a side of receiver heat is by complete filling, that is, upper container part 902 occupies the totality volume of this container.Draw having no solar energy input experience heat of Fig. 9 B is extracted the system 900 after period of one section elongation out: this hole insulation door 912 seals; To reduce loss to environment; And after cloudy daytime and night, demarcation strip has moved up, and a cold side 914 is full.Figure 10 depicts the position of demarcation strip in the circulation of two day/night: one " desirable daytime " and one almost are cloudy " daytimes of transition ".As general rule, when the instantaneous solar energy input of receiver 900 was extracted out speed less than heat, demarcation strip moved up in case, to keep the temperature distribution of needs between volume heat and cold; When this solar energy input was extracted speed out greater than heat, demarcation strip moved down in receiver.

Demarcation strip 906 is raised usually and descend, and makes demarcation strip keep constant substantially with the relevant temperature of following fused salt (each temperature on the container appropriate section by on average) 906 or more like this, or within (usually being narrow) prescribed limit.Make the temperature stabilization (although the volume of salt changes in this part) of the fused salt of heat in the top, can realize continuous heat extraction, and need not to change the thermodynamic process parameter of power cycle.If any net heat gain (heat of being imported and being extracted out from fused salt by solar energy causes) of receiver; With the heat gain balance of the fused salt of displacement from the lower to the upper part (promptly; Equate substantially); And on the contrary, if any net heat loss of receiver equals then generally to avoid the temperature variation in top and/or the bottom from the fused salt thermal losses partly of top displacement to the bottom of this container substantially.

Figure 11 illustrates the control strategy of the vertical position of demarcation strip, its realize flowing to or the heat of the net heat of outflow system and the salt volume of transferring to displacement between the balance of needs.Suppose this plate during preset time interval Δ t with constant speed v _PlateMove, its position change distance, delta z=v _PlateΔ t.The volume of the salt displacement that causes is Δ z and demarcation strip area A _PlateProduct.Make the temperature of temperature reservoir portion above the temperature of following reservoir portion becomes of the volume of displacement, or conversely, desired heat depends on the density p of salt _SaltWith specific heat capacity c _Salt, and the salt of heat and the temperature difference Δ T:Q=ρ between the cold salt _Saltv _PlateΔ tA _Platec _SaltΔ T.The net heat note of during time Δ t, adding receiver to is with ∑ Q _Sys, therefore the speed of the plate that then during above-mentioned interval, needs be:

v _plate=∑Q _sys/(ρ _saltΔtA _platec _saltΔT)

If the net heat flux is positive, then demarcation strip moves down; If the net heat flux is born, then demarcation strip moves up.

According to the container receiver that is separated of each various embodiment of the present invention, the loose radial clearance of definition between demarcation strip and container wall is beneficial to the flexibility of making and supporting to operate usually.More little at interval, the speed that salt flows through is generally big more, and the flow resistance and the tractive force that therefore act on demarcation strip are also big more.To constant demarcation strip speed, the speed that spills salt is inversely proportional to the annular space area.To gap delta radially _GapMuch smaller than case diameter D _TankCylindrical case, this annular space area can be approximately:

A _gap=πD _tankδ _gap

The total volumetric flow that spills salt at interval is the volume flow Q through heat exchanger _HXMove demarcation strip by the volume sum of the salt of displacement with passing through, this demarcation strip works as piston:

Q _gap=Q _HX+πD _tank ²·v _plate

Therefore the mean velocity of annular salt flowage be:

v _gap=Q _gap/A _gap

Act on the estimation of the tractive force of demarcation strip, can obtain according to following formula:

F=1/2ρ _saltv _gap ²C _dA _plate=1/2ρ _saltQ _gap ²C _dA _plate/A _gap ²

Here C _dBe the traction coeficient relevant with geometrical shape.To the circular flat board perpendicular to flow of liquid, traction coeficient C _dBe 1.12.Can see from this last equation, square increase of tractive force and spacer area, that is with being inversely proportional to, spacer area is more little, and tractive force is big more.Bigger tractive force on demarcation strip requires bigger positioning control actuator again, can increase the cost of system like this.In addition, very little interval can make receiver be easy to freezing of salt, or another kind makes the immotile mechanical bond form of this system between demarcation strip and container wall.On the other hand, loose radial clearance causes low-down flow velocity between demarcation strip and the container wall.The plate that the creep of this low viscosity fused salt is flowed and moved through is slowly bestowed the tractive force of plate usually and can be ignored.

Annular space is except that its impact to the fixing of receiver cost and operation, and it generally also has appreciable impact to systematic function.Gap, interval shown in figure 12, different causes different flows and mixed mode.The illustration of Figure 12 (i) illustrates wide gap, and it causes the weak stratiform plume of slow flowing velocity of crossing demarcation strip and unmixing cold salt.On the other hand, the illustration of Figure 12 (ii) draws and compares littler gap, and the plume of its well-mixed through guaranteeing cold salt obtains even temperature in the top of container; Cold salt has enough momentum to penetrate the far salt district that gets into heat, and the complete turbulent person's character of stratiform turbulent flow transition or plume promotes the salt volume well-mixed with heat.The cold salt in various different interval gap upwards " injections " more low-density heat salt and the turbulence scale and the character (like composition and temperature) of mixing, demarcation strip speed and salt that cause can easily be simulated and sign with the known method of those skilled in the art.In addition, possible plume geometrical shape, liquid entrainments and mixes and the plume extended corner, can from before being derived of publication about buoyancy-driven stratiform thermal plume and turbulent flow heat and the works that sprays plume.For example see people such as Moses " An experimental study of laminar plume ", J.Fluid Mech., vol., 251; People's such as pp.581-601 (1993) and Pera " Laminar plume interactions ", J.Fluid Mech.; Vol., 68, part 2; Pp.259-271 (1975), these documents this paper quotes at this, and is for reference.

Figure 13 illustrates the design process of hot receiver demarcation strip with flow chart.This process comprises: confirm to cause the gap size of the mixability of needs, then to tractive force and temperature gap on the operating temperature range of selected this system of interval calculation.If tractive force is unacceptablely high, then dwindle this radial clearance.This process is repeated iteration, till having found in the acceptable compromise between high mixing and the low tractive force.Randomly, the face structure that the design of plate improves with cover coat or flow then is such as perforation, groove or other improved shape.Then these adjustment, be radial clearance by fine tuning, with the tractive force that obtains once more fully to mix and allow the two.

Demarcation strip can improve by various different modes.For example, the flat heat of Concentric plate demarcation strip geometrical shape and separating of physics can be used for example by-pass hole or the suitably perforation change of size.Equally, bypass groove or the groove that separates regularly can be made into a fan-shaped side that places demarcation strip, cause plume unstability and the different zones of flowing that promote to mix with foundation.In addition, the bottom surface of this plate can be made into nonplanar; For example fluted and protruding or recessed profile groove can be used to directing flow to the district that needs.Also have, in certain embodiments, the upper surface of demarcation strip has texture, be coated and/or oxidized, to strengthen solar absorptance and to reduce specular reflectivity.The various various combinations and the displacement of these configurations can be used, to obtain special effect.

3. fused salt synthetic

The synthetic of the salt that expectation is used in each various embodiment comprises monobasic, binary and the ternary synthetic of three types of salt: chloride salt, carbonite and fluoride salt.Suitable Binary Chloride salt example is the eutectic mixture of KCl of NaCl and the 50mol% of 50mol%, and its fusing point is that 657 ° of C and operating range are up to 1100 ° of C.Suitable triplex carbonate for example is the Li of 32wt.% ₂CO ₃, 33wt.% Na ₂CO ₃K with 35wt.% ₂CO ₃Mixture, its fusing point is that 432 ° of C and operating range are up to 950 ° of C.Traditional nitric acid/nitrite is such as the KNO of 53wt.% ₃, 40wt.% NaNO ₂NaNO with 7wt.% ₃Mixture, be not suitable for usually being selected in, because they decompose during near 600 ° of C in temperature.

The kind of preferred salt satisfies some key requests: they all have the operating temperature of wide range, on the solar spectrum relevant wavelength, are translucent; And chemically with material around (that is, container wall and lid) and with air up to the temperature of at least 1000 ° of C be compatible.In addition, they are relatively cheap and low toxicity arranged.According to various thermal physicss and character optics of some embodiment's exemplary salt, and with traditional nitric acid/nitrite relatively, draw up in table 1.

Table 1 ( ^*NaCl and Li ₂CO ₃-Na ₂CO ₃-K ₂CO ₃Be at 800 ° of C; * KNO ₃-NaNO ₂-NaNO ₃Be at 350 ° of C)

Chloride salt can react with moisture when high temperature, produces small amount of H Cl.Add the little hydrogen oxide to this fused salt,, can make this effect reduce to minimum such as NaOH.

In each various embodiment, the selection of the salt that uses in the receiver is the operating parameter according to the solar electric power system.Preferably, fused salt has low melting point and high degradation temperature, and this degradation temperature is more than the maximum steam temperature that will be produced.Salt in heat is pumped into the place that steam generator becomes " cold " then, and the total energy that can be stored is the quality of " heat " and " cold " salt temperature and salt and the function of specific heat.If steam be from coiled pipe that the container of fused salt contacts produce, then this energy that is stored will be that salt makes cold salt sink to the function of the vertical resolution of bottom in case, water gets into coiled pipe in this bottom, and hot salt rests on the top that steam leaves coiled pipe.

Generally speaking, high temp. salt such as chloride salt, has the melting point near steam temperature, is heated to the temperature than the hotter hundreds of degree of steam temperature to salt so the energy that is stored depends on.The storage of many hours of process even a couple of days; " heat " salt temperature difference between the temperature when temperature when finishing in a day and the sun begin to heat salt again; Be very high ideally, in the magnitude of 300 ° of C to 400 ° of C, the volume of the salt that requires like this is minimum.In addition, open wide when being used in the air ambient when this salt is in, this salt is hopeful not degrade, and will degrade in time and increases system cost because use the solid window to separate salt and air.

In one embodiment, salt mixture comprises sodium chloride and the potassium chloride by 1:1 ratio (mass ratio).This cheap mixture the have an appointment eutectic melting point of 670 ° of C and the boiling point of about 1400 ° of C; Therefore, it is desirable to producing superheated vapor.In addition, it is extremely durable: unlike nitrate, if overheated it can decompose; Also unlike burning, break or tired boiler tube, it can not be destroyed in fact.In addition, because the NaCl/KCl salt mixture is transparent relatively, it will set up the convection current mixing when solar flux increases, thereby cause the self-stabilization of system, that is, reach the good homogeneous temperature distribution and avoid local superheating.

In certain embodiments, this salt synthetic also comprises nano particle, and this nano particle improves the thermal capacity and the thermal conductivity of this synthetic, and increases the sunlight damping coefficient, thereby is beneficial to the absorption of solar energy at whole whole volumes in this pond.For example, hope the concentration of nano particle in the adjustment pond,, rather than receiving wall or bottom below the surface in pond so that solar energy mainly is absorbed.Through the concentration of adjustment particle, best bulk absorbs and distributes and can obtain easily.Through the air curtain of discussing above adopting, the pond is by the atmospheric pollution of dust-laden or dirt, and the variation of the power absorption of following distribution, can be postponed or reduction.

This nano particle can by oxide material (such as, for example, aluminium oxide, silica, zirconium oxide, titanium dioxide and their composite); Metal (such as; For example, gold, silver, platinum, copper, aluminium and their alloy), and/or other refractory materials (such as; For example, graphite or diamond) process.They can be elongated nanometric rod, nanometer plate and nanotube, perhaps can be spherical, oblate or prolate shape shape.Preferably, at least one characteristic size of particle is in 1 to 1000 nanometer range.The interpolation of nano particle can increase viscosity and the thermal expansion coefficient that reduces synthetic, and this thermal expansion coefficient can hinder natural circulation and the mixing in the pond.In addition, they can increase density, can such as pump, cause heavier supporting requirement to system unit like this.For limiting these effects, particle concentration can be limited in, below 5% volume, or below 3% volume, or below 1% volume.

The selection of the particle that in the salt synthetic, uses generally depends on the particular system requirement, and can constitute the compromise between the various different considerations.Based on the particle of oxide and carbon, compare with particle based on metal, can have chemically the more advantage of inertia, thereby more can be compatible with fused salt.On the other hand, metal and diamond particles are desirable to the bigger raising of thermal conductivity.In the metallic type, precious metal has higher chemical stability than aluminium and copper usually, but also follows higher cost.There is the particle of high Elongation can provide higher thermal conductivity to improve, but also can presents higher viscosity.The benefit of less particle can be, their dispersion and dispersed phase ratio than macroparticle are more easily by stable.

Thermal energy storage with convert mechanical or electrical energy into

In each various embodiment, the receiver utilization can tolerate and surpass 700 ° of C, preferably surpasses temperature and the Undec fused salt synthetic (comprising, for example carbonite and/or chloride salt) of 1000 ° of C.A kind of like this high temperature synthetic helps high density solar energy to heat energy conversion.In addition, it can realize the high density thermal energy storage: the thermal capacity of fused salt between peak value receiver temperature and power cycle temperature (this temperature for example can be 600 ° of C), be used to stored energy, and the power cycle when supplying the sun not shine is used.Because these reasons, high temperature melting salt synthetic can increase overall system efficiency.

Yet, on the temperature of 700 ° of thermmal storage medium more than the C, be normally used for vaporific many materials and system, will be damaged or destroy, thereby can not be used.This restriction of transfer of heat system commonly used can be overcome through improvement shown in figure 14.In the embodiment that this shows; Fused salt from the heat of solar receiver; In short distance, be directed; Conduit through being processed by pottery, carbon synthetic, silicon carbide or other high temperature materials gets into the not mixer of motion component, there it and the mixing than the refrigerant body of identical synthetic.The result is that the temperature of mixture is lowered.For example, the salt of the heat of 1000 ° of C of first temperature is arranged, can mix, obtain the fused salt of 700 ° of C of the 3rd temperature with the ratio of the colder salt that 600 ° of C of second temperature are arranged by 1:3.Then, this mixture can pass through heat exchanger, and there, mixture thermal cycle in the second level for example in the steam circulation, is shifted its some heat energy to water, and this steam circulation converts heat the rotational energy of steam turbine to, and finally becomes electric energy.Mixture temperature further reduces in heat exchanger.After leaving heat exchanger, this fused salt can be broken down into first flow and second flow, and first flow is used to refill full solar receiver, and second flow is recovered, and gets into the storage tank of the colder fused salt that keeps second temperature.

In certain embodiments, this power cycle is direct air brayton cycle, and it can use the commercial technology of buying, the technology implementation of for example buying from various different turbo machine sellers.Opposite with water-cooled circulation commonly used, directly air circulation discharges atmosphere the warm air of use is direct.Such drying is cooled to the solar electric power system tangible benefit is provided, and such solar electric power system usually is arranged on extremely hot and dry area (such as the desert), and water source there is very limited.

To high temp. salt (as, help approximately or surpass the salt of the operating temperature of 700 ° of C), directly the air brayton cycle can be used, and eliminates and must use cooling water for this power cycle low-temperature heat source to be provided.With the salt inlet temperature of about 704 ° of C of power cycle and the outlet temperature of about 600 ° of C, this cycle efficiency is roughly that one kind of 40%-afford to spend operates in significantly higher efficient of ratio in lower temperature range drying cooling power cycle commonly used.Yet this cycle efficiency depends on the temperature range that heat is transferred into power cycle above that consumingly, and on the lower temperature of traditional solar electric power tower poor efficiency very.For example, 500 ° of C peak value fused salt temperature, this efficient has only 32%.On the other hand; If there is cooling water available; Closed Bretton power cycle (as; Supercritical carbon dioxide circulation) can be used, cause having the efficient of about 43-44% of the peak value carbon dioxide temperature of 550 ° of C, and the efficient of 47-48% with peak value carbon dioxide temperature of 650 ° of C.The temperature of corresponding fused salt will exceed 10-20 ° of C.The above shows, uses the solar electric power system of high temperature melting salt can use relatively little efficient sacrifice, eliminates water-cooled dependence.

5. for example

Example 1: solar-energy collecting device and thermal energy storage system

Table 2-5 provides the system design parameters according to a solar electric power embodiment of system of the present invention, and this system comprises the heliostat installed on the hillside and based on the receiver of the KCl mixture of the NaCl/50wt.% of the use 50wt.% on ground.This system can obtain continuous (" 24/7 ") MW electric power output.Its requires to be used for about 72 acres of total land area of heliostat place and receiver.Several such systems can side by side be provided with, and their heat output can be transported to central vapor turbo machine and generator unit via high temperature, the combination of HCS pipeline.Collecting heat energy from different receivers, and take heat energy the method for central vapor factory to, is well known in the art.

Table 2 is listed space and the optical design parameter and the various different performance characteristic of solar electric power system.At this,, take into account: the spacing of the heliostat of avoiding covering and block according to the calculating of the performance parameter of design parameter; And the cosine effect of heliostat and the heliostat inclination of requirement on the relative Yushan Hill of the sun, get into the receiver hole with the guiding sunlight.The geometry of these types and optical calculation are that those skilled in the art are known.

The beeline (m) of heliostat at the bottom of the mountain	20
		The longest distance (m) of heliostat at the bottom of the mountain	400
Heliostat is from the longest distance (m) in receiver hole	575
		Heliostat area (the m of every total projection ²）	55,728
Optical efficiency	90%
		The angle of the sun more than the horizon (°)	80
The distance (m) of receiver at the bottom of the mountain	200
		The angle on mountain (°)	35
The heliostat arc across angle (°)	90

The quantity of heliostat arc sheet	2
		Azimythal angle heliostat packaging density	0.7
The quantity that heliostat is capable	89
		Effective soil blanketing fctor	21.1%
The land area (hectare) of hillside heliostat arc	29
		24/7/365 average sunshine (W/m ²）	200
24/7/365 average available thermal power (kW)	11,146
		Clean all solar energy is to electrical power efficiency	29%
The quality (metric ton) of the salt that 24/7 operation requires	5,457
		Clean average 24/7 electric power (MW) that produces	4.95
Every kWeh require the quality (metric ton) of salt	45.9

Table 2

Table 3 is summarized soil (especially soil, the hillside) requirement of this system.Can see, require to produce the hillside area of the essential important percentage power in southwestern u s. state, be appropriate relatively, provides the wide region in available federal soil, wherein is the hilly country mostly,

Clean 24/7 electric power (We/m ²）	20
		Total-power requirement (GW)	500
The gross area requires (km ²）	25,000
		Upwards distance on the hillside	500
The slope on mountain (°)	35
		The quantity of heliostat arc sheet	2
Total absolute altitude (m)	574
		The hillside crow flight distance (km) that requires	25,000
The soil strip width (km) of a system	100
		The quantity of soil band	250

Table 3

Table 4 is listed the typical heat operating parameter of this system.The salt degree of depth is maintained at less than 4m because sunlight can not penetration ratio in such as the salt of 50% NaCl/KCl the darker degree of depth of the degree of depth.If other limpider salt compatible with the incident power level with same high temperature is available, then there is darker salt pond to be used than minor diameter, cause the higher thermal efficiency probably.Because as storage means; Have only sensible heat to be used; The density of low-cost massive material and the product of specific heat are then in narrow relatively scope, so the size of heat storage system has Special Significance, therefore; High differential temperatures (that is, between the minimum and maximum temperature of thermmal storage medium poor) is essential.

System temperature
		The maximum temperature of thermmal storage medium (° C)	900
The minimum temperature of thermmal storage medium (° C)	650
		Environment temperature (° C)	20

		The cylindrical stored container
The storage cycle (h) that needs	24
		Container height (m)	3.2
Total volume (the m that requires ³）	3,583
		Container diameter (m)	38

		The storage potentiality of 50%NaCl/KCl
Thermmal storage medium density (kg/m ³）	1,523
		The specific heat of thermmal storage medium (J/kg K)	1,089
Thermmal storage medium gross mass (metric ton)	5,457
		The energy that is stored (J)	1.49·10 ¹²
24/7 available average store heat power (W)	17,195,776

Table 4

Table 5 shows the design parameter of heat exchanger plate, and this plate can be attached to the wall of the cylindrical case that holds salt in certain embodiments.This table shows the relatively thinner or usefulness not even at " window " on the pond-on steel container interior fire protection brick lining, so that this heat exchanger can be attached with the zone that reduces hot path length-the be quantity that has a due proportion of with the pond of power demand.In other words, this system's ratio is good and design is feasible.

The thermal power (MWt) that vapor system requires	17
		Width (m)	2.5
Highly (m)	4
		HX wall thickness (m)	0.04
HX plate effective thermal conductivity k (W/m-K)	17
		Cross over the temperature of HX plate and fall (K)	100
The power (W) that every window is extracted out	425,000
		Necessary window quantity	40
Inner container diameter (m)	40
		HX pitch spacing/HX width	1.3
The heat exchanger unit quantity that can settle	40

Table 5

Example 2: the hot receiver of separation

Table 6 provides an embodiment's of solar electric power system (for example, as shown in Fig. 9 A and the 9B) of the case that is separated system design parameters.This system reaches output of 4MW electric power and thermmal storage in 40 hours, and this demarcation strip is coupled with and is used for " rib " that structure strengthens.Be incubated the refractory material by adding, or by adding a cover the metal tube structure, it is made into easily approximate floating with meeting ground to one or both sides.

Table 6

Some embodiment of the present invention is described, and persons skilled in the art should be understood that other embodiments that quote the disclosed notion of this paper, can be used and without departing from the spirit and scope of the present invention.Therefore, should think in all respects that the embodiment who has described is illustrative and unrestricted.

Claims

1. solar receiver comprises:

Container has the inside that is fit to hold solar absorptive material, and this container definition is radiated on this solar absorptive material to allow solar radiation along the perforate on its top;

Lid is placed on this container, one of at least is formed into oral pore in this container and this lid, with the permission solar radiation from wherein passing through; With

Cooling system is used to impel the solar absorptive material of the vaporization that at least a portion is collected along the downside of lid to condense.

2. the receiver of claim 1 also comprises at least one convection current trigger unit, is placed on or near the bottom of this internal tank.

3. the receiver of claim 2, wherein this convection current trigger unit comprises conical element substantially.

4. the system of claim 1 wherein is somebody's turn to do the downside that covers and is fit to this internal tank reflected illumination solar radiation above that.

5. the system of claim 4, wherein the downside of this lid forms the concentrator of non-imaging.

6. the system of claim 5, wherein this concentrator comprises the downside with this lid that is collected the solar absorptive material that condenses combination on it.

7. the system of claim 1, wherein this lid is fit to return to the solar absorptive material that at least a portion is condensed the inside of this container.

8. the system of claim 1 also comprises the door that is used to close this inlet opening, with the heat energy loss of reduction from this receiver, and stops the mass transfer through this hole.

9. the system of claim 1 also comprises the air curtain of crossing over the inlet opening, with the heat energy loss of reduction from this receiver, and reduces the mass transfer through this hole.

10. catch the method for solar energy to be used to generate electricity for one kind, the method comprising the steps of:

The inlet opening of guiding solar radiation through receiver, this inlet opening by container be placed on forming one of at least in the lid on this container, this container has the inside of the exposure that solar absorptive material is wherein arranged;

Cooling should be covered, and made the vapor condenses that produces from the solar absorptive material of liquefaction; With

Returned at least a portion by condensing vapour the inside of this container.

11. the method for claim 10 also comprises being deposited on the step that solar absorptive material that this lid downside solidified melts.

12. the method for claim 11 wherein should fusing step, leaves causing one of at least in the solar radiation of the upper surface of material in the receiver by the solar radiation of direct irradiation on the material that has solidified and reflection.

13. the method for claim 10 also comprises the step that forms the air curtain of crossing over the inlet opening, with the heat energy loss of reduction from this receiver, and reduces the mass transfer through this inlet opening.

14. the method for claim 10 also comprises using being placed on or near at least one convection current trigger unit of the bottom of this internal tank, the step of bringing out the convection current of phase-change material in this container.

15. a solar receiver comprises:

Structure of container is fit to hold and seals fused salt substantially, and this structure of container definition allows solar radiation inlet opening from wherein passing through; With

The demarcation strip that can vertically move flatly is placed in this structure of container, so that be divided into the upper and lower to this structure of container, this demarcation strip forms the annular space space, and it allows fused salt between the upper and lower of this container, to flow.

16. the solar receiver of claim 15 also comprises the door that is used to close this inlet opening.

17. the solar receiver of claim 15 also comprises the vertical motion actuating system, is used to control the vertical position of this demarcation strip.

18. the solar receiver of claim 17 also comprises controller, is used to drive this actuating system so that move this demarcation strip.

19. the solar receiver of claim 18; Wherein this controller moves this demarcation strip; Make when solar energy to be added, and from a side pumping salt of this demarcation strip heat, through heat exchanger; And get back to the cold side of demarcation strip and when extracting heat energy out, make the salt on the side of this demarcation strip heat keep steady temperature substantially.

20. the solar receiver of claim 19, wherein this controller moves this demarcation strip, makes the position of this demarcation strip, substantially with this structure of container in the border that is layered as between the fusing salt deposit of hot and cold by thermic overlap.

21. the solar receiver of claim 15, wherein this demarcation strip comprises anticorrosive and alloy creep.

22. the solar receiver of claim 15, wherein this demarcation strip comprises steel plate with ribbing.

23. the solar receiver of claim 15, wherein this demarcation strip comprises insulation refractory ceramics layer.

24. the solar receiver of claim 15, wherein this demarcation strip comprises hollow tubular structure.

25. the solar receiver of claim 15, wherein this demarcation strip is when this receiver is melted salt when being full of, and is floating with meeting ground basically.

26. the solar receiver of claim 15, wherein the upper surface of this demarcation strip be veined, be coated with oxidized in one of at least, to strengthen solar absorptance and to reduce specular reflectivity.

27. the solar receiver of claim 15, wherein the radial dimension in this annular space space is selected, so that prevent the mechanical bond between demarcation strip and the container substantially.

28. the solar receiver of claim 15, wherein the radial dimension in this annular space space is selected, and makes the relative movement of demarcation strip in the container, promotes the salt plume to discharge and the mixing on the hot side of demarcation strip.

29. a method that stores solar energy, the method comprising the steps of:

Keeping being capped of fused salt to receive solar energy in the container, heat the fused salt in this container top thus;

The demarcation strip of mobile and horizontal vertically; This demarcation strip separates the top of container and bottom; And reserve the annular space space; Supply the salt flow therein, so that between the mean temperature of the fused salt constantly in the mean temperature of the fused salt in this top and this bottom, keep minimum temperature difference at least; With

Heat extraction in the fused salt from the top of this container.

30. the method for claim 29, heat extraction wherein comprises that top pumping heat fusing salt from this container to heat exchanger, returns to colder fused salt the bottom of this container again from this heat exchanger.

31. the method for claim 29, wherein the total volume of fused salt in the upper and lower of this container is held constant basically.

32. the method for claim 29 also comprises the step of the lid that cools off this container effectively.

33. the method for claim 32 also comprises the heat that use is extracted out from the lid of this container that is cooled effectively, in one of power cycle and desalination circulation, makes the working fluid preheating at least.

34. the method for claim 32 comprises that also the salt that makes vaporization condenses at the downside of the lid that is cooled effectively.

35. the method for claim 29 also comprises, according to the intensity that is capped the solar energy of the defined inlet opening of container through this, opens and closes the door of this inlet opening.

36. the solar electric power system of a convergence comprises:

Based on the solar receiver on ground, being fit to hold solar energy converting is the solar absorptive material of heat; With

A plurality of heliostats, the solar radiation that is configured to make irradiation directly, do not have more multiple reflection ground, reflect the into inside of receiver through the hole of receiver.

37. the system of claim 36 also comprises solar absorptive material, and wherein this solar absorptive material comprises phase-change material.

38. the system of claim 37, wherein this phase-change material is translucent.

39. the system of claim 37, the phase-change material that wherein is in liquid form comprises fused salt.

40. the system of claim 39, wherein this fused salt is selected from the group that chloride salt, fluoride salt, carbonite, nitrite and their mixture are formed.

41. the system of claim 40, wherein this fused salt is a chloride salt, and this phase-change material also comprises hydroxide, when coming in contact with humid air with this fused salt of box lunch, and the generation of reduction HCl.

42. the system of claim 36, wherein this solar absorptive material comprises nanoparticle mixture, to improve its solar radiative absorption characteristic.

43. the system of claim 36, wherein this heliostat be positioned in receiver hole top the absolute altitude place and be directed so that mainly be directed into the surface of solar absorptive material through the solar radiation in this hole.

44. the system of claim 43, wherein this heliostat is installed on the hillside.

45. the system of claim 36, wherein this receiver is embedded in the ground at least in part.

46. the system of claim 36, wherein this receiver comprises container and is placed lid on it.

47. the system of claim 46, wherein this heliostat is placed on the absolute altitude place below the receiver and is directed, so that be drawn towards the downside of this lid through the solar radiation in this hole.

48. the system of claim 36 wherein should be configured to help the heating solar absorbent material and arrive at least about the temperature in 1000 ℃ of scopes to about 600 ℃ based on the receiver on ground and heliostat together.

49. a solar-energy conversion systems comprises:

Solar receiver is fit to hold that to be used for solar energy converting be the solar absorptive material of heat energy;

Heat exchanger, be fit to from the transfer of heat energy of the solar absorptive material of liquefaction to working liquid body, be used for producing mechanical energy with electric energy one of at least; With

Mixing chamber is fit to make the solar absorptive material of liquefaction to mix with colder solar absorptive material from heat exchanger outlet, so that before being sent to heat exchanger, reduces the temperature of the solar absorptive material of this liquefaction.

50. the system of claim 49 also comprises the thermal energy storage storehouse that is communicated with the receiver fluid.

51. the system of claim 49 also comprises being in the middle of heat exchanger and the mixing chamber and the thermal energy storage storehouse that is communicated with heat exchanger and mixing chamber fluid.

52. the system of claim 49, wherein this solar receiver be fit to hold temperature about 600 ℃ at least about the phase-change material in 1000 ℃ of scopes.

53. the system of claim 49 also comprises the thermal power transfer of working fluid being the turbo machine of mechanical energy.

54. the system of claim 49 also comprises by this turbine driven generator, makes mechanical energy convert electric energy into.

55. one kind is used and assembles the energy-producing method of solar electric power system, the method comprising the steps of:

Press the hole entering solar receiver of individual reflection guiding solar radiation through solar receiver; So that in receiver, be heated to solar-energy collecting at about 600 ℃ to the solar absorptive material that comprises in the receiver thus and arrive at least about the temperature in 1000 ℃ of scopes;

Transfer to working fluid to heat energy from heated solar absorptive material; With

Use this working fluid produce mechanical energy with electric energy in one of at least.

56. the method for claim 55, heat energy wherein is being transferred to working fluid above on about 700 ℃ temperature.

57. the method for claim 56, wherein this working fluid comprises air, and this energy produces the direct air Bretton of step utilization power cycle.

58. the method for claim 57, wherein this Bretton power cycle does not require water-cooled.

59. the method for claim 55, wherein this heat energy is transferred to working fluid from heated solar absorptive material in heat exchanger.

60. the method for claim 59; Also comprise the solar absorptive material that makes from the liquefaction of receiver; Mix with colder solar absorptive material,, reduce the temperature of the solar absorptive material of liquefaction so that before being sent to heat exchanger from heat exchanger outlet.